Twilio

Twilio is a cloud communications platform that provides programmable voice, messaging, and video services. Rapida integrates with Twilio to enable AI-powered phone conversations — both inbound (customers call your Twilio number) and outbound (your assistant calls customers).

Twilio uses WebSocket media streams for real-time audio. When a call connects, Twilio opens a WebSocket to Rapida carrying μ-law encoded audio at 8kHz. Rapida handles all codec conversion and resampling transparently.

How It Works

Prerequisites

Twilio Account

An active Twilio account with at least one phone number

Rapida Account

An active Rapida account with a configured voice assistant

You will need your Twilio Account SID and Auth Token, which you can find on the Twilio Console dashboard.

Step 1: Set Up Provider Credentials

First, store your Twilio API credentials in Rapida so the platform can authenticate with Twilio for outbound calls and webhook validation.

Navigate to External Integrations

Go to Integration > Tools in the Rapida dashboard. You will see a grid of available external integrations.

Select Twilio

Find the Twilio card and click “Setup Credential”.

Enter Your Twilio Credentials

A modal will appear. Fill in the following fields:

Field	Description	Where to Find
Key Name	A friendly name for this credential (e.g., “Production Twilio”)	Your choice
Account Token	Your Twilio Auth Token	Twilio Console → Auth Token
Account SID	Your Twilio Account SID	Twilio Console → Account SID

Click “Configure” to save.

Verify Connection

After saving, the Twilio card should display “Connected”. Click on it to see credential details, last updated time, and management options.

Step 2: Configure Phone Deployment

With credentials saved, configure your assistant’s phone deployment to use Twilio.

Open Your Assistant

Navigate to Assistants and select the assistant you want to deploy via phone.

Go to Phone Deployment

Click “Deploy” → “Phone” to open the phone deployment configuration page.

Select Twilio as Telephony Provider

In the Telephony section:

Select Twilio from the telephony provider dropdown
Choose the Twilio credential you created in Step 1 from the Credential dropdown
Enter your Phone number — this is the Twilio phone number that will receive inbound calls and serve as the caller ID for outbound calls (e.g., +15551234567)

Configure Experience Settings

Set up the conversation experience:

Setting	Description	Default
Greeting	The first message the AI speaks when answering	(optional)
Error Message	Message spoken when an error occurs	(optional)
Idle Timeout	Seconds before prompting an idle caller	`30`
Idle Message	Message spoken when caller is idle	`"Are you there?"`
Idle Timeout Retries	How many times to retry before ending call	`2`
Max Call Duration	Maximum call length in seconds	`300`

Configure Audio Providers

Select your Speech-to-Text (STT) and Text-to-Speech (TTS) providers. These determine how audio is transcribed and synthesized during the call.

For Twilio calls, audio arrives in μ-law 8kHz format. Rapida automatically resamples to 16kHz for the STT provider and converts TTS output back to μ-law for Twilio.

Save Deployment

Click “Deploy” to save. Your assistant is now ready to handle phone calls via Twilio.

Step 3: Configure Your Twilio Phone Number

Point your Twilio phone number’s webhook to Rapida so incoming calls are routed to your AI assistant.

Open Twilio Console

Go to Twilio Console → Phone Numbers → Active Numbers and select your phone number.

Set Voice Webhook

Under Voice Configuration, set:

Field	Value
A call comes in	Webhook
URL	`https://websocket-01.in.rapida.ai/v1/talk/twilio/call/{your-assistant-id}?x-api-key={your-api-key}`
HTTP Method	`POST`

Replace {your-assistant-id} with your Rapida assistant ID.

Set Status Callback (Optional)

To receive call lifecycle events (ringing, answered, completed):

Field	Value
Status Callback URL	`https://websocket-01.in.rapida.ai/v1/talk/twilio/ctx/{contextId}/event?x-api-key={your-api-key}`
Status Callback Events	`initiated`, `ringing`, `answered`, `completed`

The status callback URL uses a contextId returned during the call setup. Twilio sends events to this URL automatically when configured in TwiML.

Save

Click Save in the Twilio console. Your phone number is now connected to Rapida.

Making Outbound Calls

Once your phone deployment is configured, you can initiate outbound calls using the Rapida API or SDKs.

Python
Node.js
cURL

from rapida import Rapida

client = Rapida(api_key="rpd-xxx-your-key")

call = client.calls.create(
    assistant_id=123456789,
    to_number="+15551234567",
    from_number="+15559876543",  # optional, uses deployment default
    metadata={"campaign": "follow-up"},
)

print(f"Call queued: conversation_id={call.conversation.id}")

import { Rapida } from 'rapida';

const client = new Rapida({ apiKey: 'rpd-xxx-your-key' });

const call = await client.calls.create({
  assistantId: 123456789,
  toNumber: '+15551234567',
  fromNumber: '+15559876543',
  metadata: { campaign: 'follow-up' },
});

console.log(`Call queued: ${call.conversation.id}`);

curl -X POST https://api.rapida.ai/v1/talk/call \
  -H "Authorization: Bearer rpd-xxx-your-key" \
  -H "Content-Type: application/json" \
  -d '{
    "assistant": { "assistant_id": 123456789 },
    "to_number": "+15551234567",
    "from_number": "+15559876543",
    "metadata": { "campaign": "follow-up" }
  }'

Features

Feature	Description
Inbound Calls	Customers call your Twilio number and speak with your AI assistant
Outbound Calls	Initiate calls programmatically via SDK or API
Real-time Streaming	Bidirectional audio via Twilio Media Streams (WebSocket)
Call Recording	Automatic conversation capture for review and compliance
Status Callbacks	Receive call lifecycle events (ringing, answered, completed)
WhatsApp	Send and receive WhatsApp messages via Twilio
Global Numbers	Use Twilio phone numbers from 100+ countries

Troubleshooting

Calls go to voicemail instead of Rapida

Verify the webhook URL in your Twilio phone number configuration
Ensure the URL uses https:// and the correct assistant ID
Check that your Rapida API key is valid

One-way audio or no audio

Verify your Twilio credential (Account SID + Auth Token) is correct in Rapida
Check that your STT and TTS providers are configured in the phone deployment
Ensure the assistant has an active version with a valid LLM provider

Outbound calls fail

Verify the Twilio credential is connected in Integration > Tools
Ensure the from_number is a valid Twilio phone number in your account
Check that the phone deployment is configured and saved

Status callbacks not received

Ensure the status callback URL is configured in Twilio console
Verify the URL format: https://websocket-01.in.rapida.ai/v1/talk/twilio/ctx/{contextId}/event?x-api-key={your-api-key}
Check Twilio’s Debugger for webhook errors

Create an Assistant

Build your voice AI assistant

Phone Deployment

Overview of phone deployment options

Outbound Call API

API reference for creating calls

Conversation Logs

View call history and transcripts

For more information on Twilio’s platform, visit the Twilio Developer Documentation.

Assistants

Knowledge

LLM Endpoint

Activity & Logs

External Integrations

Credentials

Workspace

Governance

Deployment Options

How It Works

Prerequisites

Twilio Account

Rapida Account

Step 1: Set Up Provider Credentials

Step 2: Configure Phone Deployment

Step 3: Configure Your Twilio Phone Number

Making Outbound Calls

Features

Troubleshooting

Create an Assistant

Phone Deployment

Outbound Call API

Conversation Logs

​How It Works

​Prerequisites

Twilio Account

Rapida Account

​Step 1: Set Up Provider Credentials

​Step 2: Configure Phone Deployment

​Step 3: Configure Your Twilio Phone Number

​Making Outbound Calls

​Features

​Troubleshooting

​Related Resources

Create an Assistant

Phone Deployment

Outbound Call API

Conversation Logs

How It Works

Prerequisites

Step 1: Set Up Provider Credentials

Step 2: Configure Phone Deployment

Step 3: Configure Your Twilio Phone Number

Making Outbound Calls

Features

Troubleshooting

Related Resources